There is one name -- and one name only -- in the highly competitive field of gyros. That name is Steve's. With just a closet-sized booth in a corner of the West Side Market and but two menu items -- regular and large -- Steve's is nonetheless the New York Yankees of the gyro world. The pita bread is fresh, the meat is sliced before your very eyes, and the taste is rent-raising good. For four bucks, you'll get a gyro big enough to feed a Pacific island nation, and that's just the regular. It is unknown whether anyone has actually eaten the large and lived to tell about it.